A light emitting device, such as a semiconductor injection laser or light emitting diode, is typically soldered to a substrate which may be a header or an intermediate such as metallized beryllium oxide (BeO) or diamond which is, in turn, soldered to the header. Preferably, an emitting facet of the device is accurately aligned with an edge of the substrate in order to eliminate partial reflection of an emitted light beam from a substrate, to allow an optical fiber to be brought into close proximity with the emitting facet or to facilitate the alignment of the device with other system components. This alignment is, however, difficult to attain because of the small size of the device and because the device tends to float on the molten solder and move away from its initial accurate alignment to the substrate edge. To realign the facet edge requires moving the device on the molten solder which is both time consuming and risks damage to the device itself.
Thus, it would be desirable to have a method of soldering a light emitting device to a substrate which maintains an accurate alignment of the device and substrate during the melting and solidification of the solder.